pyrimidine synthesis

Question 1

what is the chemical structure of pyrimidines and what are the different types ?

Answer 1

contains 1 carbon ring
cytosine
thymidine
uridine

Question 2

how is UMP made ?

Answer 2

start off with glutamine
converted to carbamoyl phosphate
into orotic acid + PRPP
and then into UMP using UMP synthase

Question 3

where is TMP and CMP derived from ?

Answer 3

derived from UMP

Question 4

what is the enzyme that catalyzes the reaction between glutamine and carbamoyl synthase ?

Answer 4

carbamoyl synthetase II
CPS 1

Question 5

what is the difference between CPS 1 and CCPS 2 ?

Answer 5

CPS 1 is found in the liver and is pat of the urea cycle
CPS 2 is involved in pyrimidine synthesis and is found in most cells

Question 6

what disease is associated with a dysfunction in UMP synthase ?

Answer 6

orotic aciduria

Question 7

what other disease is commonly confused with orotic aciduria ?

Answer 7

OTC deficiency

Question 8

what is the main difference between orotic aciduria and OTC deficiency ?

Answer 8

raised ammonia levels in OT defeciency

Question 9

what is the treatment for orotic aciduria ?

Answer 9

uridine

Question 10

what are the clinical features associated with orotic aciduria ?

Answer 10

high levels off orotic acid in urine
megaloblastic anemia

Question 11

when should i suspect orotic aciduria ?

Answer 11

in a baby with megaloblastic anemia that is not responding too folate treatment

Question 12

what are the sources of the 1 ring formation in pyrimidines ?

Answer 12

carbamoyl phosphate
aspartate

Question 13

what drug is associated with blocking thee conversion of carbamoyl phosphate to orotic acid ?

Answer 13

leflunomide